Permeability test container



Dec. 15, 1953 Vany M. D. BRAZIER PERMEABILITY TEST CONTAINER Filed 0G12.6, 1951 lee/ fZO

IN VEN TOR. MAR/0N D. @RAZ/ER 3` nel. QW, 5M

ATTORNEY Petented Dec. l5, 1953 UNITED Sfii'i PATENT @FMCE to EetroleuinEngineering Associates, Inc.,

Pasadena, Calif., a corporation of California Appiication ctober 6,1951, Serial No. ),l29

(Cl. i3- 38) 3 Claims. 1 f 's invention is directed to a coni inerprinin handling unconso.` ated mineral samples as frequently ofinterest, for exe, in petroleum production procedures.

n well drilling techniques it is almost always the practice to obtaincore samples peodically and spaced intervals throughout i These core areleus laboratory tests and paleonlnation to develop 'ficant data aracterof the vario, mations d by well bore. This pra 'tice is i and oi longextent. Of fiore recent ily expanding interest is the si; ilar ditchcuttings, these being mineral t removed from a well bore with thedrilling fluid.

In many cases core samples or ditch cuttings are unconsolidated.Unconsolidated specimens are relatively soft and very susceptible todeterioration on handling. Heretofore it has been substantiallyimpossible to obtain the above inentioned laboratory data from suchunconsolidated samples because of the fairly rugged treatment to whichthese samples are exposed in sampling, transportation, storage andtesting. It is obvious, however, that samples of this nature are equallyvaluable in plotting the characteristics of a given traverse as the moreeasily handled consolidated cores or cuttings.

I have now developed a container specifically adapted to sampling,retention and storage of unconsolidated and soft mineral materials whichpermits the acquisition of suitable samples of such materials and thesubsequent testing therefor for permeability, etc. Without danger ofphysical deterioration ordinarily consequent upon their unconsolidatednature.

In accordance with the invention I provide a container comprising acylindrical member, a ne mesh wire screen affixed across one end of thecylinder, a cap member adapted to be removable held across the other endof the cylinder and having an opening therein giving access to thecylinder, and a second ne mesh wire screen disposed across this opening.This second screen may be affixed to the cap member around the edges ofthe opening therein or may be held across the cylindrical member by thecap niember provided that the screen is removable from the cylindricalmember upon removal of the cap member.

An important feature of the container is that it may be used insubsurface sampling. Ordinarily core samples or ditch cuttings areobtained at the surface of the Well after removing a core from aconventional core barrel or after screening the ditch cuttings from thecirculating drilling duid. However, it is possible with the containerdescribed herein and as modilied for this particular purpose, to obtainsamples of unconsolidated formations directly from the well bore. Insuch practice the container is inserted in the well bore in suitablecarrying means and is driven into the particular unconsolidatedformation as by a mechanical means or an explosive charge. In thisfashion a sam-r ple of the unconsolidated material is enclosed withinthe container which, upon withdrawal from the formation, is capped ashereinafter described.

The invention will be clearly understood from the following detaileddescription of the accompanyng drawings, in which:

Fig. l is a sectional elevation of one embodiment of the invention; and

Fig. 2 is a sectional elevation of a somewhat different embodiment ofthe invention specically adapted for subsurface sampling.

The container shown in Fig. l comprises a cylinder l preferably of metaland having a Jline mesh wire screen il affixed across one open endthereof. A cap i2 is adapted to be removably mounted over the other openend of the cylinder ld, the cap and cylinder forming a friction joint asillustrated. The cap may, as an alternative, be removably held on thecylinder by conventional screw threads or a fractional turn retainingmeans. rIhe manner of affixing the cap is not critical providing it isremovable, although for reasons hereinafter made apparent, excessiveirregularities in the exterior surface of the cylinder are preferablyavoided.

The cap i?. has an opening or port it therethrough giving access to theinterior of the cylinder. In this particular embodiment a second finemesh Wire screen l is afxed to the inside face of the cap across theopening Eli. The screens il and l5 are conveniently affixed to thecylinder and cap respectively by brazing, soldering or the like asindicated at it and l' respectively of the drawing. Preferably the edgeof the capped end of the cylinder it is beveled to form an annular knifeedge i3 which serves the double purpose of facilitating the obtainmentof the sample as hereinaftei1 described and of providing a substantiallyfluid-tight seal with the cap.

The interior surface H3A of the cylinder l is I preferably of roughtexture corresponding generally to conventional knurling. Although suchtreatment of the interior cylinder surface is not essential, it doeshave advantages as will be apparent hereinafter.

In using the container of Fig. 1 to obtain a sample of an unconsolidatedmaterial at the surface of a Well bore, for example, the cap l2 isremoved and the cylinder le, is forced into a body of the designatedunconsolidated material with the knife edge i3 facilitating suchinsertion. It is important that the cylinder enter the sample withoutunduly rearranging the grain structure thereof, such entry being insuredby the leading knife edge. The cylinder is then removed from the body ofunconsolidated material retaining the sample therein or, depending uponthe charaoteristics of the material, the excess may be broken away fromthe exterior of the cylinder. A smooth exterior surface is also desiredto fa. cilitate entry of the cylinder in the material and for thisreason a friction t between the cap and the body is preferred.

When the sample is retained within the cylinder in the manner describedabove, the cap is affixed thereon and the sampling is complete. If anyappreciable time interval is to elapse prior to laboratory testing ofthe sample thus retained, it is desirable to seal the container inairtight means, as is generally conventional in any core samplingtechniques.

The container is unique in enabling the acquisition of unconsolidatedsamples and the testing thereof, the testing being carried out withoutremoval of the sample from the container. Testing of the unconsolidatedsample, as for example to obtain the permeability thereof, is madepossible by reason of the existence and nature of the une mesh screenenclosing the open ends of the capped cylinder. The nature of thesescreens is highly important, it being essential that they be ofsufficiently fine mesh to retain the finest particles of theunconsolidated sample. Such particles are commonly known as silt A 250mesh screen is satisfactory for some samples, but a 325 mesh screen ispreferred as being sufficiently fine to retain the finest particles ofsubstantially all samples recovered. It is further important that thescreen be not so fine as to affect the permeability measurements of thesample. In this respect the screen mesh sise should not be appreciablyfiner than 350 mesh.

A mesh size of approximately 325 is thus preferred, having both of theabove mentioned factors in mind, since this mesh will retain silt insubstantially all samples and will not affect permeability. In addition,this particular mesh size has the further advantage of impermeability towater at small pressure differentials, thereby minimising undesirablemoisture loss from the retained sample,

The desirability of providing the container with a rough interiorsurface was mentioned above. The purpose of this surface is to obtain arelatively tight seal between the retainedsample and the container wallsso as to avoid. channeling of the fiuids used to measure permeabilityalong the container Walls. Because of the unconsolidated nature of thesamples with which the subi ject container is used, deformation thereofin accordance With surface irregularities of the con tainer is insured,thereby automatically` prevente ing channeling at this inter-face.

The container as illustrated in Fig. l is adapted principally to surfacesampling. By very minor modifications thereof, and as illustratedk inFig. 2,

4 the container may be used to obtain samples from the well bore itselfwithout the intervening steps of coring or migration in the drillingfluid.

The container shown in Fig. 2 comprises a cylinder 2t preferably having,as in the foregoing embodiment, a rough interior'surface. A fine meshscreen 2| is aflixed across one end of the cylinder and a perforatemetal plate 22 is affixed across the same end of the cylinder to providea mechanical support for the screen 2l. Many modifications can be madein the container with respect to the relationship between the screen 2tand the metal plate 22, it being essential only that the screen coverthe one or more perforations in the metal plate and that the plate bejuxtaposed to and so as to protect the screen. The reason why suchsupport is required will be apparent from the description of the use ofthe container. The opposite end of the cylinder 29 is knife edged as inthe foregoing embodiment, and is provided with a removable cap 2lihaving an opening 25 giving access to the interior of the cylinder andhaving a fine mesh screen 26 sealed thereacross. A number ofsemi-flexible fingers 23 are affixed at one end to the inside wall ofthe cylinder adjacent the knife edged end thereof and are positioned todepend into the cylinder and to normally project inwardly from the wallthereof.

In employing the container of Fig. 2 for subsurface sampling, thecontainer with the cap 2i removed is lowered into the well bore bysuitable supporting means and is driven into the particular formation tobe sampled, generally on a radius of the bore. The driving force may oefurnished by mechanical means triggered by remote control or by anexplosive charge in an arrangement similar to a gun perfolallor. Thefingers 26 are, at the moment of insertion of the cylinder, displacedagainst the Walls of the cylinder and, come into play as the cylinder'is retracted to retain in the cylinder the sample housed therein uponforceful insertion of the cylinder into the formation. The metal plate22 serves to limit the insertion of the cylinder and is required becausein many instances the fine mosh screen 2i ls not strong enough towithstand the shock attendant upon the required method of insertion.rThe plate 22 also forms a convenient anchorage for a cable or othermeans for withdrawing the cylinder from the formation after the forcefulinsertion as above described. Upon returning the cylinder thus ioaded tothe surface, the capr is placed over the appropriate end in the mannerabove described and the encased sample is ready for handling as in theembodiment of 1.

The container of the invention was designed particularly for use in oilproduction techniques and particularly in the drilling and logging ofoil Wells, but will find use with equal facility under any circumstanceswherein an unconsolidated mineral sample is desired, and may besatisfactorily characterized by tests performed thereon without removalfrom the container. It is, of course, apparent in any such proceduresthat the Weight of the acquired sample is important in the measurementof saturation and the like., such weight being easily ascertained by aforeknowledge of the precise Weight of the individual containers.Conveniently, When these containers are made in large numbers, theweight is stamped or engraved thereon as being substantially invariantduring the life of the container.

I claim:

1. In a device for taking a core sample of a relatively unconsolidatedporous material conf taining fine particles and for determining thepermeability of the sample thus taken, the combination which comprises arigid tube of uniform interior cross section, one end of the tube beingopen and adapted for driving into the material to obtain the sample andthe interior surface of the tube being rough so as to obtain arelatively tight seal between the contained sample and the tube, and ascreen disposed across and afiixzed to the tube remote from its openend.

2. In a device for taking a core sample of a relatively unconsolidatedporous material containing line particles and for determining thepermeability of the sample thus taken, the combination which comprisesa, rigid tube of uniform interior cross section, one end of the tubebeing open and adapted for driving into the material to obtain thesample and the interior surface of the tube being rough so as to providea relatively tight seal between the sample and the tube, and a screen ofZ50-325 mesh disposed across and aiixed to the tube remote from its openend.

3. In a device for taking a core sample of a relatively unconsolidatedporous material containing fine particles and for determining thepermeability of the sample thus taken, the combination which comprises arigid tube of uni= form interior cross section, one end of the tubebeing open and adapted for driving into the material to obtain thesample within the tube and the interior surface of the tube being roughso as to provide a, relatively tight seal between the contained sampleand the tube, a screen disposed across and afxed to the tube remote fromits open end, the perforations of the screen being in the range of250-325 mesh, a removable cap for the open end of the tube, said caphaving an opening across it and a screen disposed in said f opening.

MARION D. BRAZIER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,251,909 Lindsay Aug. 12, 1941 2,392,637 Boehler Jan. 8, 19462,498,198 Beeson Feb. 2l, 1950 2,509,883 Rolshausen et al. May 30, 19502,541,785 Smith iiii Feb. 13. 1951

